Investing in factory automation for the first time is a big decision for many CNC machine shops. For Loveridge Machine (Salt Lake City, UT), owner Dennis Loveridge thoroughly researched his options before making a decision for his high tech job shop. Loveridge clearly defined what the company wanted to achieve in automating a key work cell, shared this information with six different machine tool suppliers, and carefully evaluated the results with son and general manager David Loveridge and his staff. In the end, Loveridge Machine chose to work with Okuma distributor Hartwig Inc. (St. Louis).
According to Hartwig sales engineer Scott Clinger, “This was truly a team effort that included Okuma, Gosiger Automation, Renishaw Inc. and Caron Engineering—all working closely with Loveridge Machine to create the most effective automated solution. The result is a system that the customer tells us reduces their labor costs for these parts by 50%.”
Loveridge Machine has been a successful, family-owned high-tech CNC machine shop since 1975, making complex prototypes and medium size production runs for such diverse industries as aerospace, automotive, defense, oil fields, and roller coasters. The company even had a role in the Hubble telescope and the space shuttles.
Since 2000, the company has produced 30,000 parts per year for an illumination flare used by the US military. Dave Loveridge said: “Each year, the tolerances, cost and delivery requirements for these parts become more challenging, especially because machining these items is very labor intensive. Each part has a short cycle time so the machine operators aren’t able to do other work in between cycles. This adds up to a lot of wasted time. We decided we needed to look into automating this process so we could reduce labor costs for each part, and free our people to work on other tasks. We chose Hartwig because their proposal satisfied all of our demands and they convinced us that the Okuma CNC lathe was the best solution for our application.”
Hartwig’s Scott Clinger recommended the Okuma LB-3000EX-MYW CNC machine tool as the best choice for performing the various machining operations necessary to meet Loveridge’s accuracy and part volume requirements. “However, this situation demanded a lot more than a great machine tool, so I contacted our factory automation partner, Gosiger Automation in Dayton, Ohio. After I explained the customer’s requirements to Mark Eddy and his team, they designed a comprehensive solution that incorporated robotics, inspection and material handling.”
“One of the critical issues with this application is that the part starts as an aluminum impact forging and the OD to ID is not perfectly concentric. This made automating loading and unloading of parts more difficult. Another factor we wanted to address is how to automate part inspection and any necessary tool offsets,” said Loveridge.
Meeting these demands required Gosiger Automation to integrate a number of components with the Okuma lathe. The first challenge, according to Mark Eddy, was enabling the Fanuc M-10iA/10 six-axis industrial robot to properly locate and grip the forgings despite the lack of OD/ID concentricity. “The aluminum impact forgings are manually loaded onto a powered conveyor queue standing on end, hollow end up. The conveyor has fixed side rails to maintain the part positioning. At the robot end of the conveyor, a nest captures the leading part in a nesting position for robotic handling. Each of the continuous belt conveyors has a capacity of 30 parts,” said Eddy.
“After pick up, the forging is evaluated using Fanuc iR-Vision to determine the offset of the part bore from the robot-gripped O.D. This eliminates the effects of I.D. to O.D. part run out when loading the work holding. The robot, using vision feedback, then offsets the part for loading either the main or sub-spindle of the machine tool. O.D. to I.D. run out of the aluminum impacts is a maximum of 0.085″ [2 mm] and mandrel load clearance is 0.030″ [0.76 mm] at maximum material condition.
“The robot is equipped with a single, pneumatic two-jaw gripper with interchangeable chuck jaws specifically designed for these parts. The parts are gripped by their outside diameters for loading onto the sub-spindle OP10 arbor and for removal from the machine tool’s main spindle chuck. The robot system interfaces with the Okuma lathe using Ethernet I/P,” said Eddy.
To meet Loveridge’s part inspection requirements, Hartwig and Gosiger Automation chose the Renishaw Equator for its versatility, precision and reliability. The gage uses an SP25 scanning probe to take thousands of data points, much like a coordinate measuring machine (CMM). However, while most CMMs are designed for off-floor operation, the Equator was built for use in the manufacturing environment.
However, Loveridge was looking for more than part inspection, they also wanted to use this data for statistical process control (SPC). The answer was to take the data from the Renishaw Equator and process it through Caron Engineering’s AutoComp software. Ryan Hegman, national sales manager for Caron Engineering said: “After every fourth part is machined, the Fanuc robot places the part into the Renishaw Equator for scanning. The data are then sent to the AutoComp software, which processes the information and compares it to the master. If the software determines that an offset (in 10 thousandths of an inch increments) is necessary to maintain accurate machining, it works through the Okuma OSP control to make the correction. All of this happens automatically, with no operator intervention necessary.”
Automating a manufacturing process to meet specific customer wishes means pulling together a variety of resources and integrating them as seamlessly as possible. “Gosiger Automation, Renishaw and Caron all worked with us to meet the customer’s expectations. In addition, the people of Loveridge Machine were supportive and cooperative every step of the way, which is critical to this kind of installation. We all worked together to give them the results they were looking for: reduced cost-per-part, better use of their manpower and a system that keeps pumping out quality parts,” said Hartwig’s Scott Clinger.
For more information from Gosiger Automation, go to www.gosiger.com/, or phone 877-288-1538; from Hartwig Inc. go to www.hartwiginc.com/ or phone 314-426-5300; from Okuma America Corp., go to www.okuma.com/, or phone 704-588-7000; from Renishaw Inc., go to renishaw.com, or phone 847-286-9953; from Caron Engineering, go to www.caroneng.com, or phone 207-646-6071.
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